Field of the Disclosure
The present invention relates to a display device, and more particularly, to a liquid crystal display device.
Discussion of the Related Art
Generally, a liquid crystal display device displays an image by the use of thin film transistor functioning as a switching element. The liquid crystal display device is widely used for display devices of notebook computer, tablet computer, smart phone, portable display device, and portable information device as well as display devices of television or monitor. The liquid crystal display device is not a self light emitting display device, whereby a backlight unit for emitting light is disposed under a liquid crystal display panel. That is, the liquid crystal display device displays an image by the use of light emitted from the backlight unit.
FIG. 1 is a cross sectional view illustrating a related art liquid crystal display device.
Referring to FIG. 1, the related art liquid crystal display device may include a liquid crystal display panel 10, a backlight unit 20, a rear cover 30, a guide frame 40, and a front cover 50.
The liquid crystal display panel 10 may include confronting lower and upper substrates 11 and 13 bonded to each other with a liquid crystal layer interposed in-between, a lower polarizing film 15 attached to a rear surface of the lower substrate 11, and an upper polarizing film 17 attached to a front surface of the upper substrate 13.
The backlight unit 20 is disposed at a rear surface of the liquid crystal display panel 10, wherein the backlight unit 20 emits light to the liquid crystal display panel 10. The backlight unit 20 may include a light guiding plate 21 disposed at a rear surface of the liquid crystal display panel 10, a plurality of light emitting diode packages 23 for emitting light to one lateral surface of the light guiding plate 21, a reflective sheet 25 disposed at a rear surface of the light guiding plate 21, and an optical sheet portion 27 disposed on the light guiding plate 21.
The rear cover 30 receives the backlight unit 20 therein, and supports the guide frame 40.
The guide frame 40 supports a rear edge of the liquid crystal display panel 10, and covers a lateral surface of the liquid crystal display panel 10. To this end, the guide frame 40 may include a guide sidewall 41 for covering each lateral surface of the liquid crystal display panel 10 and each lateral surface of the rear cover 30, and a panel supporter 43 protruding in a rectangular frame shape from an inner lateral surface of the guide sidewall 41 and supporting the rear edge of the liquid crystal display panel 10.
The front cover 50 is connected with the guide sidewall 41 of the guide frame 40, to thereby cover a front edge portion of the liquid crystal display panel 10 and each lateral surface of the guide frame 40.
Accordingly, an interval between a display area (AA) of the liquid crystal display panel 10 and the plurality of light emitting diode packages 23 is decreased in the related art liquid crystal display device, to thereby obtain a small bezel width (BW).
However, as shown in FIGS. 2 and 3, according as an optical distance (OL) between the display area (AA) of the liquid crystal display panel 10 and the plurality of light emitting diode packages 23 is decreased in the related art liquid crystal display device, a hot spot may occur in the display area (AA) of the liquid crystal display panel 10. The hot spot may be caused by a luminance difference between a bright area (LA) which is irradiated with light emitted from the plurality of light emitting diode packages 23 and a dark area (DA) which is positioned between each of the light emitting diode packages 23 and is not irradiated with light emitted from the plurality of light emitting diode packages 23.
Also, the optical sheet portion 27 is disposed on an light-incidence portion of the light guiding plate 21 in the related art liquid crystal display device while being not fixed thereon, whereby the optical sheet portion 27 might be cracked or moved by vibration for a mechanical reliability test.
Accordingly, a front luminance defect may occur due to the hot spot in the light-incidence portion of the related art liquid crystal display device, and reliability of the related art liquid crystal display device may be lowered due to the crack or movement of the optical sheet portion 27.